LTC4212 Datasheet, PDF (1/24 Pages) Linear Technology – Hot Swap Controller with Power-Up Timeout

FEATURES
s _{Allows Safe Board Insertion and Removal}
from a Live Backplane
s _{Controls Supply Voltages from 2.5V to 16.5V}
s _{Adjustable Soft-Start with Inrush Current}
Limiting
s _{Fast Turn-Off Time}
s _{No External Gate Capacitor is Required}
s _{Power Good Input with Adjustable Timer and}
Glitch Filter
s _{Power-Up Timeout Circuit Interfaces with External}
Supply Monitors
s _{Dual Level Overcurrent Fault Protection}
s _{Automatic Retry or Latched Mode Operation}
s _{High Side Drive for an External N-Channel FET}
s _{MS10 Package}
U
APPLICATIO S
s _{Electronic Circuit Breaker}
s _{Hot Board Insertion and Removal}
s _{Self-Isolating Hot Swap Boards}
, LTC and LT are registered trademarks of Linear Technology Corporation.
Hot Swap is a trademark of Linear Technology Corporation.
LTC4212
Hot Swap Controller with
Power-Up Timeout
DESCRIPTIO
The LTC^®4212 is a Hot Swap^TM controller that allows a
board to be safely inserted and removed from a live
backplane. An internal high side switch driver controls the
gate of an external N-channel MOSFET for supply voltages
ranging from 2.5V to 16.5V. The LTC4212 provides soft-
start and inrush current limiting during the start-up
period. It features a power-up timeout circuit that discon-
nects the system supply when the onboard supplies do not
enter into regulation within an adjustable timeout period.
The controller interfaces with external supply monitor ICs
or directly with the PGOOD pin of a DC/DC converter. After
normal power-up, a programmable power good glitch
filter can be enabled to filter out short term dips in the
supplies.
Two current limit comparators provide dual level
overcurrent circuit breaker protection. The slow com-
parator trips at V_CC – 50mV and activates in 18µs. The fast
comparator trips at V_CC – 150mV and typically responds
in 500ns.
The LTC4212 can be configured for both latchoff and
autoretry applications and is available in a 10-pin MSOP
package.
TYPICAL APPLICATIO
Hot Swap Controller with Power Good Function
BACKPLANE EDGE
CONNECTOR CONNECTOR
(FEMALE) (MALE)
V_CC
5V
0.007Ω
Z1 10Ω
100nF
Si4410DY
+
10µF
5V
+ ^LT1963-2.5 +
2.5V
1.5A
10µF
10µF
FAULT
10k
10k 20k
V_CC
ON
SENSE
GATE
LTC4212
10k
+ ^LT1963-3.3
10µF
+
10µF
3.3V
1.5A
FAULT
PGI
10k
GND
TIMER
PGT
PGF
V_CCA
V_CC3
LTC1727-2.5
2.1k
COMP2.5 V_CC25
0.01µF
4.7nF
270pF
COMP3
COMP A GND
GND
Z1 = SMAJ10A (TVS)
4212 TA01a
Power-Up Waveforms
ON
5V/DIV
TIMER
1V/DIV
PGT
1V/DIV
PGI
5V/DIV
5ms/DIV
4212f
1